Preemption of sidelink resources in unlicensed bands

Abstract

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a first user equipment (UE) may transmit first sidelink control information (SCI) indicative of a first reservation of a sidelink resource corresponding to an unlicensed sidelink band. The UE may receive second SCI indicative of a second reservation of the sidelink resource. The UE may determine, based on at least one channel occupancy time (COT) associated with at least one of the first UE, the second UE, or an additional UE, a preemption status corresponding to the second reservation relative to the first reservation. The UE may perform a sidelink resource allocation operation based on the preemption status. Numerous other aspects are described.

What is claimed is: 
     
         1 . A first user equipment (UE) for wireless communication, comprising:
 a memory; and   one or more processors, coupled to the memory, configured to:
 transmit first sidelink control information (SCI) indicative of a first reservation, by the first UE for a first sidelink communication, of a sidelink resource corresponding to an unlicensed sidelink band; 
 receive second SCI indicative of a second reservation, by a second UE for a second sidelink communication, of the sidelink resource; 
 determine, based on at least one channel occupancy time (COT) associated with at least one of the first UE, the second UE, or an additional UE, a preemption status corresponding to the second reservation relative to the first reservation; and 
 perform a sidelink resource allocation operation based on the preemption status. 
   
     
     
         2 . The first UE of  claim 1 , wherein the one or more processors, to perform the sidelink resource allocation operation based on the preemption status, are configured to perform the sidelink resource allocation operation based on the first reservation being preempted by the second reservation. 
     
     
         3 . The first UE of  claim 2 , wherein the first reservation is preempted by the second reservation based on at least one preemption condition being satisfied. 
     
     
         4 . The first UE of  claim 3 , wherein the sidelink resource is not within the at least one COT, wherein the at least one COT consists of every COT associated with the first UE and every COT shared by the first UE, wherein a priority of the first sidelink communication has a first priority level and a priority of the second sidelink communication has a second priority level, wherein the first UE is configured with a sidelink preemption enablement parameter, and wherein the at least one preemption condition is satisfied based on:
 the sidelink preemption enablement parameter having a first value, and 
 the second priority level being higher than the first priority level. 
 
     
     
         5 . The first UE of  claim 3 , wherein the sidelink resource is outside the at least one COT, wherein the at least one COT consists of every COT associated with the first UE and every COT shared by the first UE, wherein a priority of the first sidelink communication has a first priority level and a priority of the second sidelink communication has a second priority level, wherein the first UE is configured with a sidelink preemption enablement parameter, and wherein the at least one preemption condition is satisfied based on:
 the sidelink preemption enablement parameter having a third priority level,   the second priority level being higher than the first priority level, and   the second priority level being higher than the third priority level.   
     
     
         6 . The first UE of  claim 3 , wherein the sidelink resource is included in the at least one COT, wherein the at least one COT comprises at least one of a COT associated with the first UE or a COT shared by the first UE, wherein a priority of the first sidelink communication has a first priority level and a priority of the second sidelink communication has a second priority level, wherein the first UE is configured with a sidelink preemption enablement parameter, and wherein the at least one preemption condition is satisfied based on:
 the sidelink preemption enablement parameter having a first value, and   the second priority level being higher than the first priority level.   
     
     
         7 . The first UE of  claim 3 , wherein the sidelink resource is included in the at least one COT, wherein the at least one COT comprises at least one of a COT associated with the first UE or a COT shared by the first UE, wherein a priority of the first sidelink communication has a first priority level and a priority of the second sidelink communication has a second priority level, wherein the first UE is configured with a sidelink preemption enablement parameter, and wherein the at least one preemption condition is satisfied based on:
 the sidelink preemption enablement parameter having a third priority level, 
 the second priority level being higher than the first priority level, and 
 the second priority level being higher than the third priority level. 
 
     
     
         8 . The first UE of  claim 3 , wherein the at least one preemption condition is satisfied based on the sidelink resource being included in the at least one COT, wherein the at least one COT comprises at least one of a COT associated with the second UE or a COT shared by the second UE. 
     
     
         9 . The first UE of  claim 8 , wherein the second SCI comprises a dedicated data field that indicates that the sidelink resource is in the at least one COT. 
     
     
         10 . The first UE of  claim 2 , wherein the one or more processors, to perform the sidelink resource allocation operation, are configured to:
 remove the sidelink resource from a first resource selection window based on the sidelink resource being preempted by the second UE; and   determine a selected resource from a set of candidate resources in a second resource selection window, wherein the selected resource is included in the at least one COT, wherein the at least one COT comprises at least one of a COT associated with the first UE or a COT shared by the first UE.   
     
     
         11 . The first UE of  claim 2 , wherein the one or more processors, to perform the sidelink resource allocation operation, are configured to:
 remove the sidelink resource from a first resource selection window based on the reserved resource being preempted by the second UE; and   determine a selected resource from a set of candidate resources in a second resource selection window, wherein the selected resource is outside the at least one COT, wherein the at least one COT comprises at least one of a COT associated with the first UE or a COT shared by the first UE.   
     
     
         12 . The first UE of  claim 2 , wherein the one or more processors, to perform the sidelink resource allocation operation based on the preemption status, are configured to perform the sidelink resource allocation operation based on the first reservation not being preempted by the second reservation. 
     
     
         13 . The first UE of  claim 12 , wherein the first reservation is not preempted by the second reservation based on the sidelink resource being outside the at least one COT, wherein the at least one COT consists of every COT associated with the second UE and every COT shared by the second UE. 
     
     
         14 . The first UE of  claim 1 , wherein the first sidelink communication is associated with a first starting time and the second sidelink communication is associated with a second starting time. 
     
     
         15 . The first UE of  claim 14 , wherein the second starting time corresponds to a beginning of the sidelink resource and wherein the first starting time corresponds to an offset from the beginning of the sidelink resource. 
     
     
         16 . The first UE of  claim 15 , wherein the second sidelink communication corresponds to a transmission time that at least partially overlaps the offset based on a successful listen before talk procedure associated with the second UE. 
     
     
         17 . The first UE of  claim 1 , wherein the one or more processors are further configured to perform a listen before talk (LBT) procedure, and wherein the one or more processors, to perform the sidelink resource allocation operation, are configured to transmit, based on a successful result of the LBT, a partial automatic gain control symbol in a first symbol of the sidelink resource. 
     
     
         18 . The first UE of  claim 1 , wherein the one or more processors are further configured to:
 perform a listen before talk (LBT) procedure; and   perform a resource selection procedure based on an unsuccessful result of the LBT procedure.   
     
     
         19 . The first UE of  claim 18 , wherein the resource selection procedure is triggered in a reference slot, and wherein the one or more processors are further configured to:
 identify a set of candidate resources in a resource selection window comprising a window opening time and a window closing time, wherein the window opening time corresponds to a first time period after the reference slot and the window closing time corresponds to a second time period after the reference slot, and wherein the second time period has a length that is no smaller than a minimum value and no larger than a remaining packet delay budget; and   determine a selected resource from the set of candidate resources.   
     
     
         20 . A method of wireless communication performed by a first user equipment (UE), comprising:
 transmitting first sidelink control information (SCI) indicative of a first reservation, by the first UE for a first sidelink communication, of a sidelink resource corresponding to an unlicensed sidelink band;   receiving second SCI indicative of a second reservation, by a second UE for a second sidelink communication, of the sidelink resource;   determining, based on at least one channel occupancy time (COT) associated with at least one of the first UE, the second UE, or an additional UE, a preemption status corresponding to the second reservation relative to the first reservation; and   performing a sidelink resource allocation operation based on the preemption status.   
     
     
         21 . The method of  claim 20 , wherein performing the sidelink resource allocation operation based on the preemption status comprises performing the sidelink resource allocation operation based on the first reservation being preempted by the second reservation. 
     
     
         22 . The method of  claim 21 , wherein the first reservation is preempted by the second reservation based on at least one preemption condition being satisfied. 
     
     
         23 . The method of  claim 22 , wherein the at least one preemption condition is satisfied based on the sidelink resource being included in the at least one COT, wherein the at least one COT comprises at least one of a COT associated with the second UE or a COT shared by the second UE. 
     
     
         24 . The method of  claim 21 , wherein performing the sidelink resource allocation operation comprises:
 removing the sidelink resource from a first resource selection window based on the sidelink resource being preempted by the second UE; and   determining a selected resource from a set of candidate resources in a second resource selection window, wherein the selected resource is included in the at least one COT, wherein the at least one COT comprises at least one of a COT associated with the first UE or a COT shared by the first UE.   
     
     
         25 . The method of  claim 21 , wherein performing the sidelink resource allocation operation comprises:
 removing the sidelink resource from a first resource selection window based on the reserved resource being preempted by the second UE; and   determining a selected resource from a set of candidate resources in a second resource selection window, wherein the selected resource is outside the at least one COT, wherein the at least one COT comprises at least one of a COT associated with the first UE or a COT shared by the first UE.   
     
     
         26 . The method of  claim 20 , wherein the first sidelink communication is associated with a first starting time and the second sidelink communication is associated with a second starting time, and wherein the second starting time corresponds to a beginning of the sidelink resource and wherein the first starting time corresponds to an offset from the beginning of the sidelink resource. 
     
     
         27 . An apparatus for wireless communication, comprising:
 means for transmitting first sidelink control information (SCI) indicative of a first reservation, by the apparatus for a first sidelink communication, of a sidelink resource corresponding to an unlicensed sidelink band;   means for receiving second SCI indicative of a second reservation, by a UE for a second sidelink communication, of the sidelink resource;   means for determining, based on at least one channel occupancy time (COT) associated with at least one of the apparatus, the UE, or an additional UE, a preemption status corresponding to the second reservation relative to the first reservation; and   means for performing a sidelink resource allocation operation based on the preemption status.   
     
     
         28 . The apparatus of  claim 27 , wherein the means for performing the sidelink resource allocation operation based on the preemption status comprises means for performing the sidelink resource allocation operation based on the first reservation being preempted by the second reservation. 
     
     
         29 . A non-transitory computer-readable medium storing a set of instructions for wireless communication, the set of instructions comprising:
 one or more instructions that, when executed by one or more processors of a first user equipment (UE), cause the UE to:
 transmit first sidelink control information (SCI) indicative of a first reservation, by the first UE for a first sidelink communication, of a sidelink resource corresponding to an unlicensed sidelink band; 
 receive second SCI indicative of a second reservation, by a second UE for a second sidelink communication, of the sidelink resource; 
 determine, based on at least one channel occupancy time (COT) associated with at least one of the first UE, the second UE, or an additional UE, a preemption status corresponding to the second reservation relative to the first reservation; and 
 perform a sidelink resource allocation operation based on the preemption status. 
   
     
     
         30 . The non-transitory computer-readable medium of  claim 29 , wherein the one or more instructions, that cause the UE to perform the sidelink resource allocation operation based on the preemption status, cause the UE to perform the sidelink resource allocation operation based on the first reservation being preempted by the second reservation.